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Andrew Clark
94518b068b
* Add stack unwinding phase for handling errors A rewrite of error handling, with semantics that more closely match stack unwinding. Errors that are thrown during the render phase unwind to the nearest error boundary, like before. But rather than synchronously unmount the children before retrying, we restart the failed subtree within the same render phase. The failed children are still unmounted (as if all their keys changed) but without an extra commit. Commit phase errors are different. They work by scheduling an error on the update queue of the error boundary. When we enter the render phase, the error is popped off the queue. The rest of the algorithm is the same. This approach is designed to work for throwing non-errors, too, though that feature is not implemented yet. * Add experimental getDerivedStateFromCatch lifecycle Fires during the render phase, so you can recover from an error within the same pass. This aligns error boundaries more closely with try-catch semantics. Let's keep this behind a feature flag until a future release. For now, the recommendation is to keep using componentDidCatch. Eventually, the advice will be to use getDerivedStateFromCatch for handling errors and componentDidCatch only for logging. * Reconcile twice to remount failed children, instead of using a boolean * Handle effect immediately after its thrown This way we don't have to store the thrown values on the effect list. * ReactFiberIncompleteWork -> ReactFiberUnwindWork * Remove startTime * Remove TypeOfException We don't need it yet. We'll reconsider once we add another exception type. * Move replay to outer catch block This moves it out of the hot path.
react-reconciler
This is an experimental package for creating custom React renderers.
Its API is not as stable as that of React, React Native, or React DOM, and does not follow the common versioning scheme.
Use it at your own risk.
API
var Reconciler = require('react-reconciler');
var ReconcilerConfig = {
// You'll need to implement some methods here.
// See below for more information and examples.
};
var MyRenderer = Reconciler(ReconcilerConfig);
var RendererPublicAPI = {
render(element, container, callback) {
// Call MyRenderer.updateContainer() to schedule changes on the roots.
// See ReactDOM, React Native, or React ART for practical examples.
}
};
module.exports = RendererPublicAPI;
Practical Examples
If these links break please file an issue and we’ll fix them. They intentionally link to the latest versions since the API is still evolving.
This third-party tutorial is relatively up-to-date and may be helpful.